It is likely that the remnants of this stellar explosion reached Earth in the last 33,000 years.
As the star nears the end of its life, it runs out of fuel and collapses under the weight of its gravity. The massive disintegration of giant stellar creatures occurs so rapidly that they produce the most powerful explosions known as supernovae.
Supernovae occur throughout the universe, and the matter released by the stellar death explosion is scattered throughout the universe in flames.
Now, a team of astronomers from the Australian National University found traces of an ancient supernova on Earth, buried deep underwater in the Indian Ocean after traveling to Earth about 33,000 years ago.
The results are detailed in a study published Monday in the Proceedings of the National Academy of Sciences.
Stars are the main source of the various chemical elements found in the universe. Almost all of the elements we know of at some point were created during the life and death of a star. Stars burn by producing helium from the hydrogen in their core. They then create heavier elements later in their life cycle, through a process known as nuclear combustion.
When a star explodes, all of its materials explode into space. Natural disasters mainly form the interstellar medium or the matter in the space between different star systems in some galaxies.
Some of these materials can travel through our solar system, and the solar system itself often passes through clouds of interstellar matter. As they pass through, some of the same materials can enter Earth, leaving traces in the planet’s geological record.
The researchers behind the new study found traces of radioactive iron isotopes in five sediment samples collected from the depths of the Indian Ocean. The iron isotope, known as 60Fe, is produced in stars and ejected into the interstellar medium during supernova explosions. This iron isotope occurs only in cosmic rays and is not produced naturally on Earth.
Astronomers say their presence in the sediments indicates that they likely traveled to Earth after the supernova explosion.
Iron has been deposited on Earth at a rate of 3.5 atoms per square centimeter per year over the past 33,000 years, according to the study. This slow sedimentation rate over a long period of time indicates that supernovae scatter iron isotopes throughout the interstellar medium.
The origin of the radioactive iron is likely to be a million years old and is a supernova that scatters dust particles that may still float through interstellar space today, the study said.
The Local Interstellar Cloud (LIC) is the most likely source of iron, and studies indicate that LIC is an interstellar cloud in the Milky Way that stretches for about 30 light-years, and our solar system has been moving through LIC for thousands of years. In fact, it’s still in the middle.
The LIC will contain the remnants of an ancient supernova, which will be directed towards Earth as our solar system moves through this giant interstellar bubble.
Astronomers say more measurements are needed to build a better timeline to determine exactly when this isotope has reached Earth, and whether this isotope has actually been stored by LIC.
